Alarm switch



May 13, 1952 H. s. MALUTICH 2,595,704

ALARM SWITCH Filed Nov. 26, 1948 mlijgiimgfm lllllllll I lllllllllllll ll /MS WIIIIII mi" f ll I l L l J" im; 'Inventorllllhlllllllx'lllllllllllllllll Patented May 13, 1952 ALARM SWITCH HarryS. Malutich, Erie, Pa., assigner to General Electric Company, acorporation of New York Application November 26, 1948, Serial No. 62,175

6 Claims.

My invention relates to alarms and more particularly to bellows-actuatedalarms.

Bellows-actuated alarms have been used for indicating various abnormalconditions. In the use of such alarms it is possible for a leak todevelop in the bellows with a resultant collapse of the bellows. Thiscollapse of the bellows, of course, renders the alarm ineffective. By myarrangement the collapse of the bellows causes an actuation of the alarmgivingI a signal identical with that resulting under abnormalconditions, so that the defective bellows will be noted and replaced.

Accordingly, it is an object of my invention to provide an improvedbellows-actuated alarm including provision for indicating failure of thebellows.

It is a further object of my invention to provide an improved alarmincluding a single arm for actuating a switch to indicate abnormalconditions and to indicate failure of the bellows.

Further objects and advantages of my invention will become apparent asthe following description proceeds and the features of novelty whichcharacterize my invention will be pointed out with particularity in theclaims annexed to and forming part of this specification.

For a better understanding of my invention reference may be had to theaccompanying drawing in whichiFig. 1 is a perspective view, partlybroken away, of a freezer cabinet incorporating my invention; Fig. 2 isa schematic diagram of an alarm circuit utilizing the device of myinvention; Fig. 3 is an elevation view of the alarm; Fig. 4 is a planview taken along the line 4 4 in Fig. 3; Fig. 5 shows the switch portionof the alarm in its closed position; and Fig. 6 shows the switch in itsopen position.

By way of illustration, I have shown my alarm applied to a home freezercabinet. In connection with home freezers it is desirable to providesome sort of alarm so that the existence of abnormally high temperatureconditions within the freezer cabinet is brought to the attention of theuser. In the illustration I have employed, the alarm is arranged so thata light, which is illuminated under normal conditions, is extinguishedon the occurrence of an abnormally high temperature in the freezer. Bymy invention, should a leak develop in the bellows, the resultantcollapse of the bellows is also effective to actuate the alarm andextinguish the light. Thus the user is informed promptly of theexistence of abnormally high temperatures in the freezer cabinet and isenabled to take proper steps to prevent spoilage of any foods storedtherein. Fur- (Cl. 20o-140) ther, the existence of a defective bellows,which would prevent the proper operation of the alarm for indicatingabnormally high temperatures, is also brought to the attention of theuser.

Referring now to Fig. 1, there is shown a freezer cabinet I including anouter shell 2 and an inner liner 3. A lid 4 is provided for closing thetop opening of the cabinet, the lid being held in closed position by alatch (not shown) operated by a handle ii. A housing 6 within which thealarm structure is enclosed is secured to the eX- terior of the outerwall 2. A thermostat bulb I is placed adjacent the refrigerated innerliner 3 of the freezer and is connected to the housing 6 by a tube 8.

A light 9 is provided in the front panel of the freezer cabinet, thislight, when illuminated, indicating that normal conditions prevailwithin the freezer cabinet. As shown in Fig. 2, the lig-ht 9 is suppliedfrom any suitable power source through a circuit including the alarmstructure, which is enclosed within the housing 6. Power is suppliedthrough lines I0 and I I. i

The alarm structure is illustrated in detail in Figs. 3 and 4. Thisstructure includes the housing 6 on one wall of which is mounted abellows I2 for actuating the alarm. The bellows is connected to thethermostatic bub 'I by the tube 8, so that the bellows expands uponincrease in the temperature within the freezer cabinet and contractsupon decrease in this temperature. The tendency of the bellows to expandis opposed by a spring I3 which acts against a circular plate I4interposed between the bellows and the spring. The compression of thespring is adjusted by a screw threaded rod I5 which is controlled by aknob I6 on the exterior of the housing Ii. Turning of the knob I6 movesa cap I'I up or down, decreasing or increasing the compression of thespringI I3-.

An arm I8, which is pivoted at I9, is provided for transmitting andamplifying the movement of the bellows for actuating a switch. Theswitch includes a stationary Contact 2U and a movable switch element 2I,which carries a movable contact 22. If desired, the terminal 20 may bein the form of a copper-coated magnet so as to give a snap actionoperation and minimize arcing at the contacts. The line I0 is connectedto a terminal 23 mounted on the wall of the housing 6, and the terminal2i) is supported on the terminal 23 by a bracket 24. The other line IIis securedto a terminal 25, also mounted on a wall of the housing 6.

In order to transmit motion of the bellows I2 and the pivoted arm I8 foroperating the switch element 2i, a switch arm or pivoted lever 26 isprovided. The switch element 2| is secured to or formed as an integralpart of the switch arm 2G. In order to mount the switch arm 26 forpivoted movement an insulating bracket 21 is secured to a wall of thehousing 6 by screws 23 or other suitable mounting devices. Theinsulating bracket 21 includes a recess 29 at its outer end, and theopen front of this recess is closed by a cover 33. rl`his cover extendsalong the bottom, one side, and front of the bracket 2T and is supportedon the bracket by a screw 3| which extends into the side of the bracket2l'. The switch arm 2% is in the form of a crank having two crank arms32 and 33, the crank arms extending in opposite directions from acentral leg 34 of the switch arm. The central leg 34 is received withinthe recess 29 for pivotally mounting the switch arm, and the central legis held in position within the recess by the cover 3Q. A iiexicle lead353 is provided from the terminal 25 to the switch arm 26 to completethe alarm circuit to the switch element 2i and the contact 22. The lead35 be secured to the terminal 25 and the switch arm in any suitablemanner, as by soldering as indicated by 36 and 3l.

A tension spring 38 is employed for biasing the switch to its closedposition. One end of the springSE is secured by a screw 39 or othersuitable fastening device to a wall of the housing S, and the other endof the spring is connected by a clip to the crank arm 33 of the switcharm 2S. lt can be seen by reference to Fig. 3 that the spring ment ofthe switch arm 2S thereby bringing the contacts 22 and 22 intoengagement to close the circuit through the light 9 from the lines i andil. A conventional control (not shown) may be employed for starting andstopping the rerigerating apparatus to maintain the temperature withinthe freeaer cabinet within a predetermined range. While the freezer isoperating within this temperature range the limited movement of the armi8 does not affect the switch, and the switch remains in its closedposition under such normal conditions. Thus, in the arrangement shown,under normal conditions, the circuit of the light 9 is closed and theresultant illumination of this light indicates the existence ofsatisfactory temperature conditions within the freezer cabinet.

In order to actuate the switch arm 2d under abnormally high temperatureconditions or upon the failure of the bellows I2 the pivoted arm i8is'provided with two ears di and 42, the ear M being adapted to engagethe crank arm 32 and the ear 42 being adapted to engage the crank arm S3for moving the switch to its open position. The ear il extends above theplane of the remainder of the pivoted, arm l2 and, under normalconditions, as illustrated in Fig. 5, the ear is spaced from the crankarm 52. The ear 42 extends below the plane of the remainder of thepivoted arm IS and, under normal conditions as illust-rated in Fig. 5,is spaced from the crank arm 33. As best illustrated in Fig. 5, thearrangement of the ears 4l and 42 relative to the crank arms S2 and 33yrespectively provides aV lost motion arrangement so that the bellows mayexpand and contract through a range corresponding to normal temperatureconditions within the freezer cabinet without having either the ear 4Ior ear 42 engage its respective crank arm. As explained above, thefreezer tempera- -3 tends to effect a clockwise moveture may bemaintained within this normal temperature range by a conventionalcontrol which starts and stops the refrigerating apparatus upon theoccurrence of predetermined maximum and minimum temperatures in thefreezer cabinet.

The operation of the alarm is as follows. Under normal conditionswherein, as explained above, the ears 4I and 42 of the pivoted arm I8are spaced out of engagement with their respective crank arms 32 and 33,the bellows may expand and contract over a limited range correspondingto the normal range of temperatures within the freezer cabinet withouthaving any eiiect on the operation of the switch. Under normalconditions the switch element 2| is biased to its closed position by thespring 38, closing the circuit of the light 9 and causing illuminationof this light. Should an abnormally high temperature occur within thefreezer cabinet the bellows moves beyond the normal limited range. Uponthe occurrence of a predetermined maximum travel of the bellows in theexpanding dlrecticn and a resultant maximum counterclockwise movement ofthe pivoted arm I8, the arm I8 reaches the position shown in Fig. 6wherein the ear 42 has engaged the crank arm 33 and continued upwardmovement of the ear 42 has moved the switch element 2! to its openposition. The alarm circuit is broken by the shifting of the contact 22out of engagement with the terminal 20, thereby extinguishing the light9 and indicating to the user the existence of such abnormal conditions.Although the alarm has been illustrated with a normally closed switch sothat the light 9 is illuminated under normal conditions, it will beapparent that, if desired, the switch arm 2! could occupy anormally-open position, being moved to the closed position forilluminating the light 9 upon failure of the bellows or upon theoccurrence of abnormal temperature conditions.

On the other hand, should a leak occur in the bellows with the resultingcollapse of the bellows, the pivoted arm I8 is moved in a clockwisedirection to the position illustrated in Fig. 3. Under this conditionthe ear 4l engages the crank arm 32 of the switch arm 25, causing thecounterclockwise movement of the switch arm and or" the switch element2|. The alarm circuit is thereby broken by the separation of thecontacts 2i? and 22 and the light is extinguished, bringing thesituation to the users attention. li, upon investigation, the user findsthat the temperature within the freezer cabinet is within the normalrange he is then aware that the extinguishing of the light has resultedfrom a failure of the bellows and the bellows can be replaced. ln theabsence of this latter arrangement the user would be unaware that thealarm was not in operating condition and any subsequently occurringabnormally high temperature conditions would go unnoticed.

While I have illustrated my invention as applied to a freezer cabinet,it will be apparent to those skilled in the art that the alarm can beused equally well to indicate other abnormal conditions such asabnormally high or low pressures, speeds, etc. coupled with anindicating of failure of the bellows. Therefore, I do not de sire myinvention to be limited to the particular construction shown anddescribed and I intend, by the appended claims, to cover allmodifications within the spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. An alarm comprising a bellows, a pivoted arm actuated by saidbellows, and a switch arm adapted to open and close an alarm circuit,said first-mentioned arm engaging said switch arm at a predeterminedextreme position in one direction of travel of said first-mentioned armfor moving said switch arm to one position, nist-mentioned arm engagingsaid switch arm at a predetermined extreme position in the oppositedirection of travel of said first-mentioned arm for moving said switcharm to said one position, said switch arm being biased to a secondposition at all times, said first-mentioned arm being disengaged fromsaid switch arm during travel intermediate said extreme positionswhere'- by said switch arm occupies said second position.

2. An alarm comprising a bellows, a pivoted arm actuated by saidbellows, and a switch arm adapted to open and close an alarm circuit,said first-mentioned arm engaging said switch arm at a predeterminedextreme position in one direction or" travel of said first-mentioned armfor moving said switch arm to its open position, said first-mentionedarm engaging said switch arm at a predetermined extreme position in theopposite direction of travel of said first-mentioned arm for moving saidswitch arm to its open position, said switch arm being biased toward itsclosed position at all times, said first-mentioned arm being disengagedfrom said switch arm during travel intermediate said extreme positionswhereby said switch arm occupies its closed position.

3. An alarm comprising a bellows, a pivoted arm actuated by saidbellows, a pivoted lever having two oppositely extending crank arms,said pivoted lever including a switch element adapted to open and closean alarm circuit, and means for biasing said switch element to itsclosed position, said pivoted arm including two ears, one of said earsbeing arranged to engage one or said crank arms after a predeterminedtravel of said pivoted arm in one direction for moving said switchelement to its open position, the other of said ears being arranged toengage the other of said crank arms after a predetermined travel of saidpivoted arm in the opposite direction for moving said switch element toits open position.

4. An alarm comprising a bellows, a pivoted arm actuated by saidbellows, a pivoted lever having two oppositely extending crank arms,said pivoted lever including a switch element adapted to open and closean alarm circuit, and means for biasing said switch element to itsclosed position, said pivoted arm including two ears, one of said earsbeing adapted to engage one of said crank arms after a predeterminedmaximum travel of said pivoted arm in one direction for moving saidswitch element to its open position, the other of said ears beingadapted to engage the other of said crank arms after a predeterminedmaximum travel of said pivoted arm in the opposite direction for movingsaid switch element to its open position, said ears being spaced fromsaid crank arms during movement of said pivoted arm under normalconditions whereby said switch element remains in its closed positionunder normal conditions.

5. An alarm comprising a bellows, a pivoted arm actuated by saidbellows, a pivoted lever having two oppositely extending crank arms,said pivoted lever including a switch element adapted to open and closean alarm circuit, and a spring connected to one of said crank arms forbiasing said switch element to its closed position, said pivoted armincluding one ear spaced from one of said crank arms during normalconditions, said pivoted arm including a second ear spaced from theother of said crank arms during normal conditions, said one ear beingadapted to engage said one of said crank arms after a predeterminedmaximum travel of said pivoted arm in one direction resulting fromabnormal expansion of said bellows under abnormal conditions for movingsaid switch element to its open position, said second ear being adaptedto engage said other of said crank arms after a predetermined travel ofsaid pivoted arm in the opposite direction resulting from collapse ofsaid bellows.

6. An alarm comprising a bellows, a pivoted arm actuated by saidbellows, a pivoted lever having two oppositely extending crank arms,said pivoted lever including a switch element adapted to open and closean alarm circuit, and means for biasing said switch element to oneposition, said pivoted arm including one ear spaced from one of saidcrank arms and a second ear spaced from the other of said crank armsproviding a lost motion arrangement whereby said ears do not engage saidpivoted lever during limited movement of said bellows under normalconditions, said ears engaging said crank arms upon predeterminedmaximum travel of said bellows in either direction for moving saidswitch element to its second position.

HARRY S. MALUTICH.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

